The present invention relates to an adjusting device for a transmission, in particular for a motor vehicle transmission, with at least one moveable adjusting element, the position of which is detected by at least one sensor, wherein a code path is provided which has sections of different heights which are provided to be scanned by the sensor.
Speed converters and also speed-torque converters and components thereof are, in this context, referred to by the term “transmission”. In particular motor vehicle main transmissions, clutches, etc. are to be covered by said term.
For controlling of transmissions of this type, input signals, produced, for example, by an operator or a controller, are converted into a mechanical movement of parts of the transmission. For example, during a change of gear speed or transmission ratio of a motor vehicle transmission, a selection and a shifting direction can be detected, can first be converted into movements of a selector lever and of a shift lever and then corresponding parts of the transmission can be moved. Conversely, the movements or positions, for example of the selector lever and shift lever, and the further part of the transmission, such as, for example, the position of the shift forks have to be sensed.
According to the prior art, displacement sensors are used for the controlling of vehicle transmissions. The displacement sensors usually have a linearly moveable pin. In this case, the sensor pin is coupled, for example, to the shift shaft in such a manner that a translatory movement of the shift fork leads to a linear movement of the sensor pin. The sensor is usually arranged in the lower oil chamber of the transmission and therefore exposed to high temperature and media loadings. For this reason, use is usually made of inductive displacement sensors which are very robust. In the case of these inductive sensors, the sensor pin moves in the interior of a coil. A movement, for example, of the shift shaft brings about a movement of the sensor pin which, in turn, causes a change in inductance in the coil. In addition to the displacement sensor design which has to be robust and costly because of the environmental conditions, solutions of the prior art give rise to further disadvantages. If there are different movements to be detected, different stroke lengths for the respective displacement sensors generally also arise. Accordingly, different embodiments of sensors have to be used. Similarly, the detection of different types of movement requires in each case different sensor types, such as, for example, for translatory and rotatory movements.
A further approach according to the prior art involves supplying the linear movement, which is to be sensed, of the shift shaft to the displacement sensor via a code path. For this purpose, sections of different heights are provided on the code path, with different heights corresponding to certain positions of the shift shaft. Said different heights are detected by a suitably arranged, linear displacement sensor.
The embodiments of the present invention provide an adjusting device for transmissions, in which positional changes caused by translatory and by rotatory movements can be detected with little outlay.
The adjusting device according to the invention improves on the prior art at least in that the sections of the code path of different heights are arranged at least two-dimensionally. Thus, given a suitable configuration of the two-dimensional code path, two movement directions which are independent of each other and the instantaneous position of the adjusting element in respect of two independent movement directions can be detected by just one sensor. In this case, for unambiguous detection, each discrete position to be detected can be assigned an unambiguous height on the two-dimensional code path. As an alternative, however, a plurality of positions of identical height may also be coded so as to form a group of positions which is to be treated identically in terms of control. If the sensor has a scanning element, the movement characteristics thereof can be matched to the characteristics of the sensor via an appropriate design of the code path sections; in particular, a rotational movement for angular detection can be converted into a linear movement. At least in some cases, this enables the number of different sensor types in an adjusting device to be reduced. The code path may also be arranged on curved surfaces, for example on shafts, thus resulting overall in a three-dimensional arrangement. For this reason, the wording “at least two-dimensionally” has been used in the present description.
In a preferred exemplary embodiment, it is provided that the adjusting element can execute both a translational movement and a rotational movement, with both an angular measurement and a linear displacement measurement taking place via the sensor. Such a combined detection of a linear displacement measurement and an angle size by a single sensor reduces the complexity of the adjusting device both in respect of the number of sensors and in respect of the outlay on evaluation.
Furthermore, it can advantageously be provided that the code path is coupled mechanically to the adjusting element or is arranged thereon. The sensor can thus detect the mechanical movement of the adjusting element, which movement is transmitted to the code path. For example, the code path may also be integrated directly into the shape of the adjusting element. This constitutes an only insignificantly higher outlay on construction and production.
In particular, an advantageous embodiment is produced in that the code path is provided to be arranged at least in some sections in an oil chamber of a transmission. This is advantageous in many cases, since the adjusting elements to be monitored are located there.
Furthermore, the invention can be advantageously implemented by the exemplary sensor being provided to be arranged at least in some sections outside an oil chamber of a transmission. The sensor can therefore be fitted outside an environment which is unfavorable for it, and therefore a more cost-effective construction form and/or a construction form having greater reliability can be selected for the sensor. For example, the sensor may be integrated into the cover of a transmission. Only the lower side of the sensor is therefore in contact with the oil chamber and exposed to the corresponding high loadings therein.
A further exemplary embodiment is developed in that a plurality of sensors is provided, the sensors being arranged at least essentially parallel to one another. The parallel orientation of a plurality of sensors makes it easier structurally to electrically connect the sensors, and simplifies the installation thereof.
In particular, the invention can preferably be implemented such that the angular positions of a selector lever and of a shift lever and the position of at least one shift fork of the transmission are detected with the plurality of sensors. All of the position information necessary for controlling the transmission can be detected in this manner.
Furthermore, it is advantageous in particular that the plurality of sensors is assigned a plurality of at least similar evaluation circuits. The use of at least similar evaluation circuits numbering as few as possible—in the ideal case only one common evaluation circuit-results in a significant reduction in costs.
In an advantageous embodiment, it can be provided that the code path is a cam path at least in some sections. This permits, for example, a direct activation of the sensor and therefore a direct transmission of the movement to be detected.
As an alternative, the invention can advantageously be implemented by the code path being designed at least in some sections as a stepless code path. This is advantageous in particular for use in automatic shift transmissions. In this case, for example, a stepless cam path for a shifting and selection movement can be arranged directly on the shift shaft which executes a rotational and a linear movement. Although the position is then not unambiguous, since only the shift cylinder or only the gate cylinder is activated, the electronic control system can assign the position unambiguously.
An advantageous exemplary embodiment also can be produced in that the sections of different heights are scanned mechanically by a scanning element coupled to the sensor. This constitutes a robust constructional type which can be produced in a simple manner.
In a likewise advantageous embodiment, it is provided that the sensor has a moveable sensor element which is coupled mechanically to the scanning element and is formed integrally therewith. A movement of the sensor element leads here to a changing output signal of the sensor. The use of a separate scanning element, for example in the form of a finger, therefore permits greater freedom of design in terms of fitting the sensor.
In another exemplary preferred embodiment, it is provided that the scanning element is prestressed in the direction of the cam path. As a result, the scanning element is in continuous mechanical contact with the cam path. The sensor can therefore reliably detect the instantaneous position or a change in position, which takes place at a particular instant, of the adjusting element.
It can likewise be provided that a plurality of sensors is assigned a corresponding plurality of cam paths having sections of different heights and a corresponding plurality of scanning elements, with the cam paths being designed in such a manner that comparable stroke movements arise for the scanning elements. On account of the comparable stroke movements, identical sensors can therefore be used despite the different movements carried out by the adjusting elements, which advantageously reduces the number of different components within the adjusting device.
A further advantageous exemplary embodiment arises in that the cam path forms at least one catch. Given an appropriate configuration of the sensor or of its elements, this permits a combination of the functions “latching” and “sensing”. In particular, latching positions can be provided at different heights on different sections of the cam path. In this case, the corresponding position of the adjusting element can be detected in the particular latching position.
In particular, it can advantageously be provided here that the scanning element simultaneously forms a latching element. The effect achieved by the scanning element carrying out the latching function is a substantial merging of latching and sensor functions and a reduction in the number of components.
Another advantageous embodiment makes provision for the sensor to be an inductive displacement sensor. Inductive displacement sensors are suitable in particular for use in environments with a high temperature and/or media loading and can detect both translational and rotational movements by using the cam path.
Furthermore, it can advantageously be provided that the sections of different heights are scanned contactlessly by the sensor. Such a complete mechanical decoupling may be advantageous under certain environmental conditions, such as, for example, during particularly great temperature fluctuations or in the event of severe vibrations.
In this connection, it can be provided, for example, that the sensor is a Hall sensor.
According to exemplary embodiments of the invention, a system is provided for detecting two independent movement directions by one sensor with the aid of a two-dimensional code path. This firstly makes it possible to reduce the number of sensors and secondly permits a simple detection of linear and of rotational movements.
Further refinements and special features of the invention are set forth in the following description of preferred embodiments.